Sunset,
Sundown

Sunset or sundown is the daily disappearance
of the Sun below the horizon in the west as a result
of Earth's rotation.

The time of sunset is defined in astronomy as the
moment the trailing edge of the Sun's disk disappears
below the horizon in the west. The ray path of light
from the setting Sun is highly distorted near the
horizon because of atmospheric refraction, making
sunset appear to occur when the Sun’s disk
is already about one diameter below the horizon.
Sunset is distinct from dusk, which is the moment
at which darkness falls, which occurs when the Sun
is approximately eighteen degrees below the horizon.
The period between sunset and dusk is called twilight.

Locations north of the Arctic Circle and south of
the Antarctic Circle experience no sunset or sunrise
at least one day of the year, when the polar day
or the polar night persist continuously for 24 hours.

Sunset creates unique atmospheric conditions such
as the often intense orange and red colors of the
Sun and the surrounding sky.

Support Us99.9% of our photos are FREE! You can download and use them for your school or personal projects, blogs, and online forums—for NO CHARGE (with just a few photos costing only $3.00 to download).